2024 American Academy of Neurology Abstract Website

Objective:

To discern whether expressing human JAG2 pathogenic variants in myoblast cultures will generate a reliable model system for muscular dystrophy.

Background:

The JAG2 gene encodes the protein Jagged2, an integral ligand in the evolutionarily conserved Notch signaling pathway. Notch signaling is critical in directing myriad developmental processes, thus pathogenic variants that compromise these pathways result in a set of serious inherited diseases. Biallelic pathogenic variants in JAG2 have recently been associated with muscular dystrophy. In the aftermath of this discovery, questions have arisen regarding the regulatory environment of JAG2 in healthy and diseased skeletal muscle and how potential therapies can be developed, necessitating the development of a suitable model system.

Design/Methods:

To explore the potential of C2C12 mouse myoblasts as an in vitro model system we developed a framework wherein both transfected and non-transfected cells were studied concurrently. We synthesized plasmids representing known JAG2 pathogenic variants and transfected them into shRNA scrambled control cells and shRNA JAG2 knockdown cells. Simultaneously, identical studies were carried out on shRNA control cells and shRNA-mediated knockdown cells devoid of any plasmid transfection. Both sets of cells underwent identical assessments of proliferation, differentiation, and downstream molecular characteristics.

Results:

We successfully constructed and transfected 3 plasmids representing severe, moderate, and mild JAG2 variants as well as empty vector and JAG2 reference sequence configurations resulting in 10 stable cell lines representing the 5 plasmids transfected into scrambled control and JAG2 shRNA cells. Significant differences in cellular growth rates between cell lines transfected with different plasmids were observed, providing initial insights into the potential role of JAG2 mutations in cellular behavior.

Conclusions:

We anticipate that our ongoing studies will illuminate the effects of specific pathogenic variants in JAG2 on skeletal muscle development in this model system, setting the stage for testing both molecular and small molecule therapies.